docs: def _popup_menu(self, icon, button, time, extended=True):
          """Handle a right click event (show the menu)."""
          m = self.create_context_menu(extended)
          m.show_all()
          m.popup(parent_menu_shell=None,
                  parent_menu_item=None,
                  func=icon.position_menu,
                  data=icon,
                  button=button,
                  activate_time=time)
          # need to store reference or menu will be destroyed before showing:
          self._m = m